Dominic Thiem beats Jack Sock to reach the fourth round of the Indian Wells Masters, where he will face Jo-Wilfried Tsonga

The fight for the final places in the fourth round of the first and grandest of the ATP Masters tournaments threw up rivalries of every shape and size.

There were two battles between France and the USA, two match-ups between Spanish compatriots, two very contrasting Germans challengers, battles between young and old and between high-ranked and low-ranked, plus plenty of home interest—no fewer than four Americans among the 16.

The two match-ups that stood out, though, were between sets of particularly interesting rivals. Young guns at the ready on Stadium 2 court, it was 22-year-old Dominic Thiem and 23-year-old Jack Sock, who met for just the second time.

In their first encounter a year ago at the same third-round stage of the Miami Masters, both were ready to make a name for themselves, Thiem ranked 52, Sock 45. The Austrian won in straight sets, reached his first Masters quarter-final, and went on to win his first three titles in quick succession, in Nice, Umag and Gstaad.

This year, Thiem had already won in Buenos Aires and Acapulco, taken the scalps of Rafael Nadal, David Ferrer and Marin Cilic, and led the tour with 21 match-wins. It all contributed to a career-high ranking of 13.

Meanwhile, Sock had also begun to fulfil his promise with a first title from two finals, as well as continuing doubles success. Straight after Miami, he won Houston, and on his return to North American hard courts in August, picked off Richard Gasquet in Washington, Grigor Dimitrov in Montreal, and finished the year with strong indoor finishes in Stockholm and Basel.

2016 started well, too. Now ranked 26, Sock beat Ferrer and Kevin Anderson to reach the Auckland final, where he retired with illness, and then also withdrew from Buenos Aires.

The two men, then, had come a long way since that first meeting, and this tussle would should how tightly-matched they were.

Both pressed hard to keep the score level at 4-4, but Thiem’s serving in particular held up well: He would drop only three points in six service games in this set. The Austrian faced down another threat to hold for 6-5, and then converted his first break chances to take the set, 7-5.

In the second set, Thiem faced and lost a break point for the first time in the third game. He regrouped to break back in the sixth, as the rallies intensified. Sock saved break points for 4-4, and it looked destined for a tie-break until Thiem threw in an error-packed game to concede a break, 5-6. Sock served for the set, but he followed a 135mph ace with a double fault, and Thiem broke back.

The Austrian, who leads the tour this year in tie-breaks, 12-3, started with a great serve-forehand-volley play, and took a 4-2 lead with a big cross-court forehand winner, but Sock edged back to work set point on serve, 6-5, and the 64-minute set went to the home favourite, 7-6(5).

But despite his heavy season, Thiem bounced back with a vengeance, breaking in the first game to begin a five-game surge. Sock broke back as Thiem served for the match, but the Austrian broke again for the match, 6-1, after two and a quarter hours—and the promise of great rivalry for the future.

Thiem credited his surge of form this year with a strong off-season, and he has certainly looked lean and fast since the start of the year. But with every big win, mental strength also increases:
“For sure the win in Acapulco gave me a lot of confidence, maybe more than Buenos Aires. Maybe I saw I could not only win titles on clay.”

He next plays No7 seed Jo-Wilfried Tsonga, who came out the better in the first French-American battle, beating Sam Querrey, 6-3, 6-4. In the other it was a different story: No9 seed John Isner beat Adrian Mannarino, 6-4, 7-6(4).

As a young new rivalry played out on Stadium 2, an older one was being replayed on Stadium 1 between No4 seed Nadal and his unseeded 32-year-old compatriot and fellow left-handed player, Fernando Verdasco.

Nadal had entirely dominated their early rivalry until 2012, winning all 13 matches. There had been great battles: Verdasco almost out-lasted Nadal in a five-set thriller at the Australian Open in 2009, and only lost out to Nadal in a three-tie-break battle in Cincinnati in 2011, 7-6(9). But the last four of their matches had all gone the distance, with Verdasco winning three of them, including another Australian Open marathon this year.

Nadal, though, was clearly up for the challenge this time, though. In fairness, the older Spaniard struggled to find his range and serve entirely in the first set: He double faulted twice in conceding the second game to love, and Nadal broke again in the fourth.

There were signs of life from Verdasco in fifth game but he could not convert his only break point of the set, and Nadal broke him again for the set, 6-0, 29 points to 13. Verdasco had made 14 errors to just four winners, and taken only seven points on his own serve.

The in-and-out form that Nadal has suffered in recent months again came to the surface at the start of the second set, with four consecutive breaks of serve. His focus eventually kicked back in with a love hold for 3-2, and they edged uneasily to a tie-break, which was almost as unpredictable as the rest of the set.

Nadal misfired to give Verdasco a 6-3 lead, but four points later, Nadal had match point. Verdasco rallied with an ace and a big forehand winner to earn another of what would become five set-point chances, but a double fault, his eighth of the match, sealed his fate: Nadal served it out 7-6(9).

Nadal’s win set up one of the most intriguing matches of the tournament so far, a first meeting with young superstar, Alexander Zverev. The charismatic 18-year-old continued to impress with his second win of the year over No16 seed Gilles Simon, having already put out No23 seed Grigor Dimitrov, and he did so in just 67 minutes, 6-2, 6-2.

In contrast, it took No18 seed, 34-year-old Feliciano Lopez, a gutsy three and a quarter hours to beat fellow Spaniard Roberto Bautista Agut, winner of two titles this year, 7-6(5), 7-6(10), 6-4.

Afterwards, he attempted to explain how he has managed to continue improving as he has aged: “Sometimes I feel better than when I was younger. I think I read the game better. Over the years, you begin to read the game faster, you know where the ball is going to go, and some other little things. Together, they make the success.”

He will need every ounce of his experience and fitness when he takes on top seed Novak Djokovic for a place in the quarter-finals. The defending champion, though, made heavy weather of beating No27 seed Philipp Kohlschreiber, 7-5, 7-5, having faltered briefly in the first set with a 4-1 lead, and then failing to convert four match points at 5-3 in the second set.

Djokovic has, though, beaten Lopez seven times, with the Spaniard scoring his only victory by retirement in Dubai last month.